JP2014221848A - Fiber-reinforced resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fiber-reinforced resin composition whereby a molded body having excellent mechanical strength can be obtained.SOLUTION: The fiber-reinforced resin composition contains 40%-90% by mass thermoplastic resin (A) and 60%-10% by mass rayon fibers (B). The component (B) rayon fibers (excluding resin-impregnated fiber bundles including rayon fibers) are dispersed in the component (A) thermoplastic resin. The component (B) rayon fibers has a fiber dimeter of 5-30 μm and a fiber length of 1-30 mm.

Description

  The present invention relates to a fiber reinforced resin composition from which a molded article having excellent mechanical strength can be obtained, and a method for producing the same.

A resin molded body is used as a metal substitute for the purpose of weight reduction, but it is known to mold a resin composition in which fibers are blended in order to increase its mechanical strength.
Patent Document 1 describes an invention of a composite material in which a thermoplastic artificial polymer having an average diameter of 5 to 20 μm and a number-weighted average length of 200 to 800 μm is blended with a thermoplastic polymer.
In the examples, TENCEL (registered trademark) is used as the cellulose-based artificial fiber.

Special table 2013-503980 gazette

  This invention makes it a subject to provide the fiber reinforced resin composition from which the molded object excellent in mechanical strength is obtained, and its manufacturing method.

As a means for solving the problems, the present invention
(A) 40 to 90% by mass of thermoplastic resin, (B) 60 to 10% by mass of rayon fiber, and (B) component rayon fiber (however, rayon fiber in component (A) thermoplastic resin) Except for resin-impregnated fiber bundles containing
(B) The fiber reinforced resin composition whose rayon fiber of a component is a thing with a fiber diameter of 5-30 micrometers and a fiber length of 1-30 mm, and its manufacturing method are provided.

  Since the molded product obtained from the fiber reinforced resin composition of the present invention is contained in a state in which the fiber length of the component (B) rayon fiber is long, it has excellent mechanical strength.

<Fiber-reinforced resin composition>
[Component (A)]
As the thermoplastic resin of the component (A), polyolefin resin, polyamide resin, styrene resin, polycarbonate resin, polyvinyl chloride, polyvinylidene chloride, polycarbonate resin, acrylic resin, methacrylic resin, polyester resin, Examples thereof include polyacetal resins and polyphenylene sulfide resins.
As the thermoplastic resin of component (A), those including those selected from polyolefin resins and polyamide resins are preferable, and those selected from polyolefin resins and polyamide resins are more preferable.

  Polyolefin resins include polypropylene, high density, low density and linear low density polyethylene, poly-1-butene, polyisobutylene, ethylene / propylene copolymer, ethylene-propylene-diene terpolymer (as raw materials) Diene component of 10% by mass or less), polymethylpentene, ethylene or propylene (50 mol% or more) and other copolymerization monomers (vinyl acetate, alkyl methacrylate, alkyl acrylate, aromatic vinyl, etc.) Random, block, and graft copolymers can be used. Among these, polypropylene is preferable.

When a polyolefin-based resin is used as the component (A), it is preferable to use an acid-modified polyolefin in combination in order to easily mix with the rayon fiber of the component (B).
As the acid-modified polyolefin, maleic acid-modified polyolefin (maleic acid-modified polypropylene) and maleic anhydride-modified polyolefin (maleic anhydride-modified polyolefin) are preferable.
When acid-modified polyolefin is used in combination as component (A), the amount of acid in component (A) (the amount of acid contained in acid-modified polyolefin in component (A)) is 0.005 on average in terms of maleic anhydride. It is preferable to mix so that it may become the range of 0.5 mass%.

The polyamide resin is preferably selected from aliphatic polyamides and aromatic polyamides.
Examples of the aliphatic polyamide include polyamide 6, polyamide 66, polyamide 69, polyamide 610, polyamide 612, polyamide 46, polyamide 11 and polyamide 12.
Aromatic polyamides include those obtained from aromatic dicarboxylic acids and aliphatic diamines or aliphatic dicarboxylic acids and aromatic diamines, such as nylon MXD (metaxylylenediamine and adipic acid), nylon 6T (hexamethylenediamine and terephthalate). Acid), nylon 6I (hexamethylenediamine and isophthalic acid), nylon 9T (nonanediamine and terephthalic acid), nylon M5T (methylpentadiamine and terephthalic acid), and nylon 10T (decamethylenediamine and terephthalic acid).
Among these, aliphatic polyamides such as polyamide 6, polyamide 69, polyamide 610, polyamide 612, polyamide 11 and polyamide 12 are preferable.

[Component (B)]
The component (B) rayon fibers described in Lenzinger Berichte 87 (2009) p98-p105 can be used. For example, viscose rayon, polynosic, modal, cupra, lyocell (Tencel), Bocell and FORTIZAN (A fiber obtained by stretching a rayon acetate [manufactured by CELANESE) and then saponifying with an alkali) or the like.
The rayon fiber of component (B) is composed of rayon fiber alone, and does not include those in which a rayon fiber bundle is impregnated with a thermoplastic resin and integrated.

  The rayon fiber (B) has a fiber diameter of 5 to 30 [mu] m, preferably 6 to 20 [mu] m, more preferably 7 to 15 [mu] m in order to increase the mechanical strength of the molded body.

Component (B) rayon fiber has a fiber length of 1 to 30 mm, preferably 2 to 15 mm, and more preferably 2 to 8 mm in order to increase the mechanical strength of the molded product.
The rayon fiber of component (B) may contain a powdery product generated by physical force applied in the production process, and therefore 90% by mass or more of the rayon fiber of component (B) in the composition is fiber. Those having a length of 1 to 30 mm are preferred, those having a fiber length of 2 to 15 mm are more preferred, and those having a fiber length of 2 to 8 mm are more preferred.
(B) The fiber length of the rayon fiber of a component is the length as a raw material used at the time of manufacture.

The X-ray orientation degree of the component (B) rayon fiber is preferably 86% or more, more preferably 90% or more.
Here, the degree of X-ray orientation is obtained from the mathematical formulas of paragraphs 0012 and 0013 of JP-A-9-31744 and paragraphs 0020 to 0021 of JP-A-9-256216.

Component (B) is a rayon fiber in which cellulose molecules are highly oriented in the longitudinal direction of the fiber (X-ray orientation degree is 86% or more), has a high tensile elastic modulus, and a high interfacial strength with the resin. Therefore, it is very excellent as a fiber for fiber reinforced resin.
The rayon fiber (B) has a strong activity on the fiber surface and a high reactivity compared to natural cellulose fiber having high crystallinity. Therefore, in order to further enhance the effect of containing the component (B), it is preferable to use an acid-modified polyolefin in combination as the component (A). By containing a functional group-containing resin such as acid-modified polyolefin as the component (A), the interfacial strength between the rayon fiber of the component (B) and the resin of the component (A) becomes higher, and the physical properties are further improved. In addition, the effect of improving physical properties by using long fibers is further increased.

The ratio in the total amount of the thermoplastic resin of the component (A) and the rayon fiber of the component (B) in the composition is:
(A) component is 40-90 mass%, (B) component is 60-10 mass%,
(A) Component 40-80 mass%, (B) Component 60-20 mass% are preferable,
(A) 50-70 mass% of component is more preferable, and (B) component 50-30 mass% is more preferable.

  The composition of the present invention includes other known flame retardants and flame retardant aids, heat stabilizers, lubricants, light stabilizers, antioxidants, colorants, mold release agents within the scope of solving the problems of the present invention. An antistatic agent can be contained.

The composition of the present invention is preferably a granulated product (spherical granulated product) obtained by solidifying the melted thermoplastic resin of component (A) to the rayon fiber of component (B).
When the composition of the present invention is a granulated product, the particle size is preferably in the range of 1 to 30 mm, more preferably in the range of 3 to 20 mm, and even more preferably in the range of 5 to 18 mm. .
When the particle size is 10 mm or more, an effect of improving the mechanical strength of the molded product is obtained, and when it is 30 mm or less, supply to the injection molding machine is stable when molding using an injection molding machine.

<Method for producing fiber-reinforced resin composition>
The manufacturing method of the above-described fiber reinforced resin composition of the present invention will be described step by step.
In the first step, the rayon fiber of component (B) is put into a mixer having rotating blades as stirring means and stirred.
The rayon fiber of component (B) is composed of rayon fiber alone, and does not include those in which a rayon fiber bundle is impregnated with a thermoplastic resin and integrated.
The rayon fiber used as a manufacturing raw material should just have a fiber diameter of 5-30 micrometers and a length of about 1-30 mm.

The mixer only needs to have rotating blades as stirring means, and preferably has heating means.
For example, Henschel mixer manufactured by Mitsui Mining Co., Ltd., FM20C / I (capacity 20L), Super mixer manufactured by Kawata Co., Ltd., SMV-20 (capacity 20L), Moriyama Manufacturing Co., Ltd., pressure kneader (DR3-10MB-E) Can be used.

  The rotating blades are usually composed of two upper blades and lower blades, or three upper blades, intermediate blades, and lower blades, but the number is not limited. The shape of the blade is not limited, but for example, the kneading type is used for the upper blade, the high circulation / high load is used for the lower blade, and the melt is used when the intermediate blade is used.

  In the first step, it is preferable to stir in the range of the average peripheral speed of the rotating blades during stirring in the range of 10 to 100 m / second, more preferably the average peripheral speed is 10 to 90 m / second, still more preferably the average peripheral speed is 10 Stir at ~ 80 m / sec.

Next, in the second step, the thermoplastic resin of the component (A) is melted by the generated frictional heat by stirring after the thermoplastic resin of the component (A) is put in the mixer, and (B) A mixture in which the thermoplastic resin (A) is adhered to the component rayon fiber is obtained.
The 1st process and the 2nd process can be made into one continuous process, without stopping stirring of a mixer.

  Friction heat is generated by stirring in the second step and the temperature in the mixer rises, so that the thermoplastic resin of component (A) melts and adheres to the rayon fiber of component (B), and the heat of component (A) A mixture of the plastic resin and the (B) component rayon fiber is obtained.

In the second step, it is preferable to stir in the range of the average peripheral speed of the rotating blades during stirring in the range of 10 to 100 m / second, more preferably the average peripheral speed is 10 to 90 m / second, and still more preferably the average peripheral speed is 10 Stir at ~ 80 m / sec.
If stirring is continued, the temperature in the mixer will continue to rise, and the power of the motor will increase. It is preferable to reduce the rotational speed by gradually or decelerating the stirring speed in accordance with the increase in power and the temperature in the mixer so that the average peripheral speed falls within the above range.

  When stirring is continued in this state, the power increases again, so the mixture is discharged to the cooling mixer used in the next third step to be connected. At this time, in this mixture, the rayon fiber of the component (B) is adhered almost uniformly in the thermoplastic resin of the component (A).

In the second step, the temperature inside the mixer is assisted to facilitate the production of the mixture of the thermoplastic resin of component (A) and the rayon fiber of component (B). It can also be warmed.
The temperature at this time is preferably about 120 to 140 ° C.

In the third step, the mixture of the component (A) and the component (B) obtained in the second step is stirred at a low speed while being cooled.
By the treatment in this step, the mixture is solidified (granulated by solidification). In the third step, in order to increase the cooling efficiency of the mixer, it is preferable to use a mixer (preferably having a cooling means) different from the mixer used in the first step and the second step.

  In the third step, it is preferable to stir in the range of 1 to 30 m / sec of the average peripheral speed of the rotating blades during stirring, more preferably 2 to 25 m / sec, more preferably 3 to 3. Stir at ~ 25 m / sec. The stirring speed in the third step is smaller than the stirring speed in the first step and the second step.

The treatment in the third step is the completion of the treatment in the third step when the mixture of the thermoplastic resin of component (A) and the rayon fiber of component (B) is solidified to the extent that it can be handled as a molding material. can do.
In addition, if the temperature inside the mixer rises too much due to the generation of frictional heat, the once solidified thermoplastic resin of component (A) will be remelted, so the temperature inside the mixer should also be controlled in the third step. Is preferred.

By the treatment in each step, a composition (granulated product) obtained by solidifying the melted thermoplastic resin (A) on the component (B) rayon fiber is obtained.
In addition, the rayon fiber of the component (B) is softer than glass fiber or carbon fiber. When the above-described manufacturing method is applied, the rayon fiber is more melted and kneaded with an extruder than when the pellet is obtained. Since it is difficult to break, when a rayon fiber having a fiber length in the range of 1 to 30 mm is used as a production raw material, the fiber length of the obtained composition (granulated product) is considered to be substantially small. It is done.

The manufacturing method described above is the same as that in paragraphs 0013 to 0041 of JP 2007-84713 A, Example 1 of the publication, paragraphs 0023 to 0043 of JP 2008-150492 A, and examples of the publication. The described manufacturing method can be applied.
When an additive other than the component (A) and the component (B) is added, it can be added in the second step or after the third step.

Further, when the composition is a granulated product, if necessary, the granulated product is further supplied to an extruder, melted and kneaded, extruded into a strand shape, and then cut into pellets (columnar shape). You can also.
The outer diameter of the pellet is preferably in the range of 1 to 10 mm, more preferably in the range of 2 to 8 mm, and still more preferably in the range of 2 to 6 mm.
The length of the pellet is preferably in the range of 1 to 30 mm, more preferably in the range of 2 to 15 mm, and still more preferably in the range of 2 to 8 mm.

  Since the molded body obtained from the composition of the present invention is lightweight and has high mechanical strength, it can be used as an alternative to metal parts used in various fields such as electrical / electronic equipment, communication equipment, automobiles, building materials, and daily necessities. It can be used, and is particularly suitable as a housing for various devices and a plate-shaped exterior material.

Examples 1 to 3, Comparative Examples 1 and 2
[First step]
Heat the heater mixer (upper blade: kneading type, lower blade: high circulation / high load, with heater and thermometer, capacity 20L, Henschel mixer FM20C / I, manufactured by Mitsui Mining Co., Ltd.) to 140 ° C. The fiber length (B) component rayon fiber shown in Table 1 and the comparative (B) component were added and stirred at an average peripheral speed of 50 m / sec.

[Second step]
Subsequently, after the polypropylene resin (including acid-modified PP) of component (A) shown in Table 1 and other components were put into the same heater mixer, stirring was continued at an average peripheral speed of 50 m / sec. The power of the motor at this time was 2.5 kW.
At about 10 minutes, power started to increase. After another minute, the power increased to 4A, so the peripheral speed was reduced to a low speed of 25 m / s. Furthermore, the power began to rise again due to continued low-speed stirring.
1 minute and 30 seconds after the start of low-speed rotation, the power reached 5 kW, so the outlet of the mixer was opened and discharged to the connected cooling mixer.

[Third step]
Cooling mixer (rotary blade: standard blade for cooling, with water cooling means (20 ° C) and thermometer, capacity 45L, cooler mixer) Stirring was started at an average peripheral speed of 10 m / sec, and the temperature in the mixer reached 80 ° C. At this point, stirring was terminated. By this step, the mixture of the component (A) polypropylene and the component (B) rayon fiber was solidified to obtain a spherical granulated product (composition) having a diameter of about 15 mm.

<(A) component>
PP (polypropylene): J139 (manufactured by Prime Polymer Co., Ltd.)
Acid-modified PP: UM1001 (manufactured by Sanyo Chemical Industries), maleic anhydride 5%

<(B) component>
-Rayon fiber 1: Bocell cut to 6 mm fiber length, fiber diameter 12 μm, X-ray orientation 93%
-Rayon fiber 2: Bocell cut to 4 mm fiber length, fiber diameter 12 μm, X-ray orientation 93%
-Rayon fiber 3: Bocell cut to 2 mm fiber length, fiber diameter 12 μm, X-ray orientation 93%
(Comparison (B) component)
Rayon fiber 4: TENCEL FCP (manufactured by Lenzing) fiber length 0.6 mm, fiber diameter 10 μm, X-ray orientation 91%
Cellulose fiber 1: NDP-T (Nippon Paper Industries Co., Ltd.), fiber diameter 20 μm,

<Other ingredients>
Antioxidant 1: Irganox 1010 (BASF Japan KK)
Antioxidant 2: IRGAFOS 168 (BASF Japan Ltd.)
Lubricant: calcium stearate

<Measurement method>
(X-ray orientation degree of rayon fiber)
The degree of X-ray orientation was determined by the transmission method. The scintillation counter was fixed at 2θ = 20.1 ° corresponding to the diffraction angle of the (101) plane, the fiber bundle was rotated perpendicular to the incident X-ray, and the diffracted X-ray intensity at the azimuth angle ψ was measured. It was calculated by the following formula described in Ott, M. Spurlin, “Cellulose and Cellulose Derivatives” 2nd.ed, Vol. II, Interscience lishers, New York (1954). In the formula, ψ _1/2 is a half-value width expressed in an azimuth angle (degrees).
fc (%) = {(1- (ψ _1/2 / 180)) × 100

(Method for preparing test piece for measuring mechanical strength)
An ISO multipurpose test piece A-shaped product (thickness 4 mm) was produced under the following conditions, and used as a test piece for each measurement described below.
Equipment: 265 / 100MSII manufactured by Mitsubishi Heavy Industries, Ltd.
Cylinder temperature 200 ° C
Mold temperature: 80 ℃
Screw diameter: 36mm

(1) Tensile strength (MPa): Measured according to ISO527.
(2) Elongation rate (%): Measured according to ISO527.
(3) Bending strength (MPa): Measured according to ISO178.
(4) Flexural modulus (MPa): Measured according to ISO178.
(5) Specific elastic modulus: flexural modulus / density (6) Charpy impact strength (kJ / m ² ): Notched Charpy impact strength was measured in accordance with ISO 179 / 1eA.
(7) Deflection temperature under load (° C.): Measured according to ISO75.

In Table 1, (A) component and (B) component are mass%, and another component is a mass part display with respect to a total of 100 mass parts of (A) component and (B) component.
As can be confirmed from Table 1, the molded product of the example containing the rayon fiber of the component (B) had higher mechanical strength than the molded product of the comparative example.

Claims (8)

(A) 40 to 90% by mass of thermoplastic resin, (B) 60 to 10% by mass of rayon fiber, and (B) component rayon fiber (however, rayon fiber in component (A) thermoplastic resin) Except for resin-impregnated fiber bundles containing
(B) The fiber reinforced resin composition whose rayon fiber of a component is a fiber diameter of 5-30 micrometers, and a fiber length of 1-30 mm.   The fiber reinforced resin composition according to claim 1, wherein the fiber reinforced resin composition is a granulated product.   The fiber-reinforced resin composition according to claim 1, wherein the rayon fiber of component (B) has a fiber length of 2 to 15 mm.   The fiber-reinforced resin composition according to claim 1, wherein the rayon fiber of component (B) has a fiber length of 2 to 8 mm.   The fiber-reinforced resin composition according to any one of claims 1 to 3, wherein the rayon fiber (B) has an X-ray orientation degree of 86% or more.   The fiber reinforced resin composition according to any one of claims 1 to 5, wherein the thermoplastic resin (A) is a polyolefin resin or a polyamide resin. It is a manufacturing method of the fiber reinforced resin composition given in any 1 paragraph of Claims 1-6,
(B) component rayon fiber (however, excluding resin-impregnated fiber bundles containing rayon fiber) is stirred in a mixer having rotating blades as a stirring means,
The thermoplastic resin of component (A) is melted by the generated frictional heat by stirring after the thermoplastic resin of component (A) is placed in the mixer, and the rayon fiber of component (B) is (A) Obtaining a mixture to which the thermoplastic resin component is attached;
Stirring the mixture at low speed while cooling,
The manufacturing method of the fiber reinforced resin composition which has this.   The method for producing a fiber-reinforced resin composition according to claim 7, wherein the mixer is a Henschel mixer or a Banbury mixer.